European Patent Specification No. 0,096,228 (largely identical in content to U.S. Pat. No. 4,538,161 to Reist) discloses an apparatus intended for addressing. In this apparatus, the conveying device is a single conveyor fitted with grippers. Each gripper conveys one printed product by seizing it at its leading edge. The trailing edge, on the other hand, slides on a slide table which is arranged in the area of an ink jet writer. The ink jet writer has a plurality of spray heads which are directed from below toward the trailing edges of the printed product which protrude laterally beyond the slide table. The ink jet writer is controlled by control signals which are produced by a transmitter coupled to the single conveyor so that inter alia, the writing speed of the ink jet writer is adapted to the conveying speed of the single conveyor. In addition, the single conveyor has allocated to it a detector which responds to empty grippers running past and then suppresses the control signal. This prevents a printed product which follows an empty gripper in the stream of printed products sliding continuously over the slide table from being inscribed with two addresses. In addition, the addresses are retrieved from an address register likewise controlling the ink jet writer.
This known apparatus has proven successful in that it is not necessary to singularize or space the stream of printed products appearing to the extent that gaps develop between successive printed products. In a singularized stream, the gaps are, for example, sensed photoelectrically in order to then trigger the start of a further inscribing operation. This is the case with the apparatus called the "Videojet Mailer," which is sold by the A. B. Dick Company, Elk Grove Village, Ill. In this arrangement, it should be noted that any singularization and the inevitable resulting increase in the conveying speed of the printed products has not proven to be satisfactory because, for example, the possible writing speed of the ink jet writer is not able to cope with the increased conveying speed. Also, after singularization, the printed products generally have to be transferred again into an imbricated formation for further processing. Further, singularization of the entire output of a modern printing press would lead to conveying speeds which are so high that they would be comparatively difficult to control and would involve the risk of damage to the individual printed products.
Additionally, Reist is not suitable for inscribing copies appearing freely supported in an imbricated stream, since an essential part of the control of the ink jet writer depends on the presence of a loaded gripper of the single conveyor.
The object of the invention is therefore to create an apparatus suitable for inscribing printed products appearing freely supported in the imbricated stream without having to singularize these printed products from the imbricated stream.